solipsist

solipsism: a theory holding that the self can know nothing but its own modifications and that the self is the only existent thing; also : extreme egocentrism

Vimes had never got on with any game much more complex than darts. Chess in particular had always annoyed him. It was the dumb way the pawns went off and slaughtered their fellow pawns while the kings lounged about doing nothing that always got to him; if only the pawns united, maybe talked the rooks round, the whole board could’ve been a republic in a dozen moves.
Thud!, Terry Pratchett, p72